The present invention relates to a forced ventilation system inside shoe sales and, more particularly, it relates to such a system including a pump inside the shoe sole activated by a walking or running activity.
Those who are involved in the shoe industry, and particularly the sport shoe industry, have the basic aim of cushioning and air circulation inside the shoe. The most important factor involved in all designs for this purpose is that generally the air suction is accomplished through pneumatic devices, generally called xe2x80x9cpumpsxe2x80x9d, formed of plastic or rubber, located in the heel area, but which do not have the necessary force for an instanteous recovery effect following each step and, at the present state of the art, do not provide for any flow conveyor capable of storing and directing the air of this area to the pump and the possibility of closing the system.
There are two possibilities of air circulation: one is to suck in outside air and inject it internally to the sole and the other is to suck the air internally in the sole and to discharge it outside. In the present description only this second situation is described because it is the more important.
In known systems, the pump, the real engine of the system, as shown in FIG. 1, generally is a bladder (1) produced by soldering or welding the edges (2 and 3) of two plastic shells, separately produced by the process of injection molding. From a hole of this bladder a tube (4) emerges. The tube, which can be formed by two half tubes (4a and 4b) soldered or welded together, has two arms (5 and 6). Arm (5) is directed toward the external edge of the sole, while arm (6) is joined to a pneumatic valve (8) which sucks air internally of the sole.
Such air circulation systems have the following drawbacks. With respect to the pumping device, bladder (1) generally has a low reactivity as a result of its construction, because of its shape and because of the material used. For these reasons it does not make the full suction within the 200 milliseconds between two steps and therefore it is only partially effective. Also, bladder (1) can not suck humidity and bad smells and its soldering may be the cause of breaking.
The system of the present invention contemplates two kinds of reactive pumping devices which instantaneously put in motion the whole system with a very strong force.
As seen in the system according to FIG. 1, the tube (6), joined to the valve (8), sucks in a random way and only in a small area (9) where there is provided no device to store and to discharge air, humidity and smells. Therefore the consequent suction is very limited.
In the system according to the present invention, a flow conveyor in the plantar area stores and conveys the air, humidity and smell through pneumatic valves joined to tubes and connected to the pump which discharges the air, humidity and smell to the outside through a pneumatic valve.
Also, the prior art systems do not provide for closing. This fact can be a problem especially at night, because, evidently each step produces a little blowing, and furthermore it is totally useless if the user wears these shoes at very low air temperature. This problem can be voided using, according to the present invention, a closing which can exclude the whole system when the user does not need it. When the system is closed, the pumping device becomes a very reactive element, being completely full of air, giving the heel area of the sole a special cushioning effect.